Outlook Classic when im clicking reply button its crashing

Question

Outlook Classic when im clicking reply button its crashing

Piolo 0

Hello,

I am experiencing an issue with Outlook Classic. Whenever I click Reply on any email, the application immediately crashes. I have tried the following without success:

Restarting Outlook

Opening Outlook in Safe Mode

Updating Microsoft Office to the latest version

Details:

Outlook version: [e.g., Outlook 2016 Classic]

Operating system: [e.g., Windows 10 Pro, 64-bit]

Steps to reproduce: Open any email → Click Reply → Outlook crashes immediately.Hello, I am experiencing an issue with Outlook Classic. Whenever I click Reply on any email, the application immediately crashes. I have tried the following without success:
- Restarting Outlook
- Opening Outlook in Safe Mode
- Updating Microsoft Office to the latest version

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Answer 1

Kha-N 1,245 Microsoft External Staff Moderator

Hi @Piolo,
Welcome to the Q&A forum, and thank you for reaching out.

I understand how inconvenient it is when Outlook Classic crashes while replying to emails. Rest assured, I’m here to help you troubleshoot this issue as effectively as possible.

To assist you better, could you please provide some additional information below:

A screenshot of the crash or any error message that appears.
Any error logs or crash reports, if available.
Does the issue also occur in New Outlook or Outlook Web, or only in Outlook Classic?
When the issue started, did it begin recently, or has it been ongoing?

In the meantime, here are a few steps you can try that have helped others in similar situations:

Create a New Outlook Profile: Sometimes, a corrupted profile can cause unexpected crashes. Creating a new profile helps isolate the issue. For more information, you can check this Article here.
Reinstall Outlook: If the installation is damaged, reinstalling Outlook can help restore stability. Make sure to back up your data before proceeding.
Roll Back to a Previous Version of Outlook: If the issue started after a recent update, reverting to a previous version may resolve the crash. You can check this Article here on how to revert back to previous Outlook version.

Please let me know how things go after trying these steps, or if you encounter any issues along the way. I’ll be glad to assist you further.

If the answer is helpful, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".

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Piolo 0 Reputation points

2025-09-15T10:04:12.0566667+00:00

Hi, this is the error im having everytime I click the new or reply message:

Faulting application name: OUTLOOK.EXE, version: 16.0.19311.20000, time stamp: 0x68c3a299

Faulting module name: mso20win32client.dll, version: 0.0.0.0, time stamp: 0x68c39c4a

Exception code: 0x1e55c3d6

Fault offset: 0x00000000002a9fcd

Faulting process id: 0x14D0

Faulting application start time: 0x1DC2626D9E2C6C4

Faulting application path: C:\Program Files\Microsoft Office\root\Office16\OUTLOOK.EXE

Faulting module path: C:\Program Files\Common Files\Microsoft Shared\Office16\mso20win32client.dll

Report Id: ee952b37-e162-426e-b37b-f727dfcbc475

Faulting package full name:

Faulting package-relative application ID:
Kha-N 1,245 Reputation points Microsoft External Staff Moderator

2025-09-15T10:33:57.4466667+00:00

Hi @Piolo,

Thank you very much for your response.

Based on the crash report you shared, it appears the issue is related to the mso20win32client.dll module. This DLL has been commonly associated with Outlook Classic crashes, particularly after recent updates.

While the specific exception code 0x1e55c3d6 is not currently documented in any Microsoft articles, the crash behavior you're experiencing closely aligns with known issues involving this module.
For workarounds, as I checked: Roll Back Outlook Classic to a Previous Version proven effective in similar cases where recent updates introduced instability.

Additionally, if you are able to, you can use New Outlook or Outlook Web in the meantime. Switching to New Outlook or Outlook Web can help you continue working without interruption while the issue is being investigated.
Also, Microsoft provides a set of automated troubleshooters for Classic Outlook that can help diagnose and fix common issues such as crashes, profile problems, or startup failures. You can check it here to see if it able to assist you on your issue.

Since this issue involves a crash with a specific exception code and DLL, I highly recommend raising a ticket to Microsoft Support Team. If you're an administrator, you can raise a support ticket directly from the Microsoft 365 Admin Center by clicking the Help & Support button. If you are not an admin, you can ask your IT admin to do so on your behalf.

As a Microsoft Q&A moderator, I have limited access to your environment and diagnostic tools. The Microsoft Support team has deeper analytics capabilities and can provide more targeted assistance for your case.

Thank you very much for your time and patience. Please let me know if the suggested workarounds help resolve the issue, or if you need further assistance. I’m here to help.

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Outlook Classic when im clicking reply button its crashing

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